Posted
by
Soulskill
on Wednesday July 17, 2013 @02:46AM
from the welcome-to-the-party dept.

Dave Knott writes "A tiny, previously unknown moon circling Neptune has been spotted by astronomers using the Hubble telescope. The moon, which is currently known as S/2004 N1, was found on July 1 by Mark Showalter of the SETI Institute in Mountain View, Calif., NASA announced Monday. It is less than 20 kilometres wide and its orbit is 105,000 kilometres from Neptune, between those of Larissa and Proteus, two of Neptune's other 14 known moons. It circles Neptune once every 23 hours."

The dividing line between "moons" and "rings" seems to be shared orbits, otherwise every little rock and/or ice ball in the outer planets' rings would have to be a "moon". A 20 km rock (or whatever) has enough gravity to sweep the space through which it passes, either clustering smaller bits into rings, adding them to its mass, or ejecting them from the planetary system.

Remember, Pluto was only a "planet" because we didn't realize it was an instance of a much larger class of KBOs. Now it appears to be more like a cluster of bits orbiting a mutual center, different from the planets and their moons, which have an orbital center deep inside the respective planets. Even without the companion bits, though, it's still a KBO.

Remember, Pluto was only a "planet" because we didn't realize it was an instance of a much larger class of KBOs. Now it appears to be more like a cluster of bits orbiting a mutual center, different from the planets and their moons, which have an orbital center deep inside the respective planets. Even without the companion bits, though, it's still a KBO.

Also, we once found a "planet" (Ceres) between Mars and Jupiter, and then another (Pallas), and then came Vesta and Hygiea. And then we realized that what was in between Mars and Jupiter was an asteroid belt.

We don't go around demanding Ceres be called a planet again because (a) it isn't, and (b) all the people who may have thought of it that was are now dead. This 'Pluto Restoration Society' will go away when those that can't adjust their mind to the reality of the universe die off. See Kuhn's "The Structu

Also, we once found a "planet" (Ceres) between Mars and Jupiter, and then another (Pallas), and then came Vesta and Hygiea. And then we realized that what was in between Mars and Jupiter was an asteroid belt.

The asteroids were known long before Pluto was discovered, though. And classified as asteroids for over a century by then.

As for which one was discovered first, Ceres was the first registered, but there are historic data hinting at Vesta having been known in earlier times - it's at times visible to the naked eye.

The asteroids were known long before Pluto was discovered, though. And classified as asteroids for over a century by then.

Perhaps more relevant... Ceres (the first asteroid) was discovered in 1801, but the increasing number of bodies discovered in that region didn't lead to the proposal and implementation of the term "asteroid" until 70-ish years later after the introduction of photography as an astronomical technique (and several years more to become accepted practice) ; Pluto was discovered in 1930, and

Remember, Pluto was only a "planet" because we didn't realize it was an instance of a much larger class of KBOs.

No, Pluto was a planet because it was a predicted discovery - it was named a planet before it was discovered. Percival Lowell calculated a possible path for "the missing planet" based on what looked like discrepancies in Neptune's orbit.

Clyde Tombaugh then found "it", and was convinced it was Lowell's Planet X. That what he found near where the incorrect calculations pointed wasn't going to have any noticeable effect on Neptune's orbit didn't stop Lowell Observatory and the press from calling it a planet.

There was no astronomical definition for "planet" at the time. Nationalism had nothing to do with it. I'm sure just about any nation is pleased when their scientists make discoveries, and with the knowledge at the time and high popularity of astronomy with the public the response was to be expected. You're looking at this through the lens of a modern elitist.

The IAU uses "moon" and "natural satellite" synonymously, which in this context refers to any natural body in a bound orbit of Neptune. I'm not sure why you think a 20km rock would fail to meet that definition.

So you are saying it is a no-go? Damn it, I had a lot of fun last time I was at the assembly in Prague. Since I am solar system specialist, for sure I would have had budget from my employer to go to Honolulu in 2015 but I guess you just ruined everything...

How about specifying it must have enough gravity to make it round to be called a moon and not just a satellite?

That would reduce the number of moons in the solar system rather dramatically. Mars, for example, would no longer have any "moons" as neither Phobos nor Deimos meet this definition. In fact both Phobos (11.1 km) and Deimos (6.2 km) are smaller than this newly discovered moon of Neptune (20 km).

Our moon doesn't even have a name.Neptunes are called "Larissa", "Proteus" or even "S/2004 N1", ours is just called "moon".It's like living in "country" in the village of "village" in a house on "street" or naming all your offspring "child".

Same problem non-name in a different language.""The moon is a moon" in English is "La luna es una luna" in Spanish.(I trust Google translate is good enough not to mess up the spanish in this simple sentence).

I don't get the point you're making about the translation. Are you saying that google translate should be able to pick up the nuance in that sentence and return a different word for moon if the Spanish use different words for our moon and a moon?

You're general point is interesting though - are there any languages that do use different words for the two?

Same problem non-name in a different language.""The moon is a moon" in English is "La luna es una luna" in Spanish.(I trust Google translate is good enough not to mess up the spanish in this simple sentence).

But, "Luna es una luna" is not just Spanish, "Luna" is latin, it just happens to be spelt the same way as a Spanish word.

Dark in "Dark Side of the Moon" means "unknown", in the same sense as "Darkest Africa" or "Dark Arts". Nobody thought the sun didn't rise in unexplored Africa - though there seems to be a convention that Dark Arts are practised at night in dark robes.

Hey, if I do my Dark Spells on the beach in a Hawaiian shirt, maybe nobody will notice. World domination, here I come!

Most significant moons in the Solar System are tidally locked with their primaries, since they orbit very closely and tidal force increases rapidly (as a cubic) with decreasing distance. Notable exceptions are the irregular outer satellites of the gas giant planets, which orbit much farther away than the large well-known moons.

Pluto and Charon are an extreme example of a tidal lock. Charon is a relatively large moon in comparison to its primary and also has a very close orbit. This has made Pluto also tidally locked to Charon. In effect, these two celestial bodies revolve around each other (their barycenter lies outside of Pluto) as if joined with a rod connecting two opposite points on their surfaces.

The tidal locking situation for asteroid moons is largely unknown, but closely orbiting binaries are expected to be tidally locked, as well as contact binaries.

Due to sitting inside it, rather than on or outside it, it had a name bases on its appearance seen from the inside long before we realised that there wer other similar things, which we saw from the outside. Though "galaxy" is only "Milky Way" in Latin.

I think the point is that the planets were named after various gods long before they were recognized as other worlds (the word planet originally meant "wandering star") Those names stuck (Neptune, Venus, Mars, etc), and by the same convention the Moon was named after the goddess Luna (or Selene, depending on the source mythology). The two remaining major celestial bodies, the Earth and Sun, get special treatment because from our perspective they are special. Earth is named after what we see of it: dirt,

Me too. The tidal forces it creates makes Earth a far more diverse place. And interestingly enough, there are biological rythms based on it. There are no other planets in our solar system with such a significant moon.

It was identified using data that was originally gathered in 2004-2009, but it was only found this year; it would appear that by convention the earliest data indicating its presence provides the discovery date, regardless of when the data was actually looked at.

Thinking of 'planets' and 'moons' is all nineteenth century 'science' - the edge of ascribing to God's plan and capturing everything observable in orderly lists, so that school-children have something to recite in groups: five continents, five senses, five races, seven seas, seven wonders of the ancient world, order species genus family class kingdom, and nine planets.

Capturing everything observable in orderly lists (based on the mechanics of the underlying model) is science. Calling planets and moons "objects" is akin to discovering more and more kinds of atoms and particles and deciding to call everything just "stuff" because it doesn't fit your model anymore. The right answer is to rethink the definitions and perhaps alter the model. The distinction between planets and moons is still a useful one even if we found a few cases where we're not sure how we should classify them.

Yes, but surely trying to classify everything into well defined groups comes up with some problem. Pluto is no longer a planet because we decided later to change the definition of planet to things that are actually big enough to clear out any other debris in their orbit. But when you compare on other traits, Pluto is more similar to Earth than Jupiter is to Earth. Jupiter doesn't even have a well defined solid surface. To put Jupiter and Earth in the same class but then leave out Pluto because of some cer

There is room for surprises, but the extension of high-pressure work on the structure of hydrogen under extreme pressures (well below the Earth's core) is reducing the room for surprises. IIRC the work was published from the HP lab at the Carnegie Institute in Washington, USA about 3 or 4 years ago, but I can't be bothered to dig out the citations.

Bullshit! People need something to relate to. You have to put fantastic phenomena in terms they understand. I'm wondering where your brain spends its time if the first thing you come up with is this sad idea. So schoolchildren can recite lists? WTF dude, you're wrong.

I remember having a discussion with my biology teacher: he claimed that humans don't have instinct - none, and why? Because the definition of 'instinct' involved stating that it didn't apply to humans. That's what these lists are: a way to win a discussion and if you can't win it, you just change the rules.

Yes, people need something they can relate to. Sure. But I'm not so sure that it would hurt if things were taught a little bit more to their specific merits: I remember how distraught I was when I learned

It's not exactly a "new moon." It's just that nobody knew it was there before. I saw another headline that said "Neptune has a new moon" but I'm sure it's been there for billions of years. I'm just sayin'...